1. Field of the Invention
This invention is related to a map display device to guiding and searching a movement route of a vehicle based on a map information, especially this invention is relate with the improvement of the display of the map information.
2. Description of the Related Art
A map is shown in a display at a conventional map display device, e.g. a conventional navigation device, a requested destination is set and a optimal guide route which links this destination and a present position of the vehicle is retrieved and is shown. Then when a route but this route are required while the vehicle is traveling this route, this another route is searched and is guided. In the search of this another route, a search cost of the road which is traveling at present is raised and the another route is re-searched by a condition which is different from a search condition of the route which is guiding at present. In this way, a road to be traveling at present is excluded and a new guide route is searched.
Also in the conventional device, when a vehicle deviates from a guide route, new route is automatically re-searched from the present position. Or when a re-search key is operated, this re-search is executed. At this conventional device, a neighborhood of a present position is searched first and a whole route is searched by a request of a user. In the search of the neighborhood, a route which returns to a previous route is searched and in a whole route searching, a whole route to the destination is searched.